Is it possible to link or append several groups of objects?
Yup, when linking or appending, just select the desired groups and they should all be loaded into your current file.
Looks like I have to select all the objects in a group to link. Once I link all the objects, is there a way to move and rotate a group of objects instead of making these local?
You should be able to rotate without making them local. You can also make proxies if that fits your need better.
In your master file, assemble the objects into a Group. Then, link to that Group, as a Group. This will link to all of the objects and to everything associated with them.
In the child-file, then make a Proxy for the individual objects that you need to manipulate.
Bear in mind the fundamental difference between Link and Append …
Thanks, it is good to know.
When I save the original file in increment and link the group of objects to another file, it there a way to update the link from another file?